In the beginning of the nineteenth century R. Nevanlinna inaugurated the value distribution theory with his famous Five value and Four value theorems which can be considered as the backbone of the modern uniqueness theory. Illuminated by these two basic results initially the research were performed on the value sharing of meromorphic functions. After five decades, uniqueness theory moved to a new direction led by F. Gross [1]}, who transformed the traditional value sharing problem to a more general set up namely to the shared set problems. Now we recall the definition of set sharing.
